Imovie event library

I can't seem to reorganize my event library.

At some point all my iPhoto videos began being automatically imported into a category called "iPhoto Videos". I don't mind that they automatically import, but they are not being organized in the sidebar by date. The iPhoto Videos category in the Event Library contains ALL videos from Mar 26, 2013 - Apr 4, 2012.

In addition to that, I have a separate category entitled "2013" with a subcategory of "January" and a sub-sub category of "Videos"...these are also not organized by date in the sidebar. Under the sub-sub category of "Videos" it contains all my videos from Jan 21, 2013-Jan 15, 2003. This makes things very difficult to find. Is there not a simple way to reorganize them? All I want is to see ALL the videos I've ever imported listed by date in the Event Library sidebar.